In recent years, a resistance change memory (ReRAM) using film resistance change is developed. As one kind of the ReRAM, a phase change memory (PRAM) using resistance value change caused by thermal phase transition between a crystalline state and an amorphous state in a film storage area is developed. Especially, a superlattice PRAM in which two different alloys are repeatedly stacked attracts attention as a memory device in which power saving is easily achieved, because phase of the film can be changed by a small current.